code: def b85decode(b):
      """Decode the base85-encoded bytes-like object or ASCII string b
  
      The result is returned as a bytes object.
      """
      global _b85dec
      # Delay the initialization of tables to not waste memory
      # if the function is never called
      if _b85dec is None:
          _b85dec = [None] * 256
          for i, c in enumerate(_b85alphabet):
              _b85dec[c] = i
  
      b = _bytes_from_decode_data(b)
      padding = (-len(b)) % 5
      b = b + b"~" * padding
      out = []
      packI = struct.Struct("!I").pack
      for i in range(0, len(b), 5):
          chunk = b[i : i + 5]
          acc = 0
          try:
              for c in chunk:
                  acc = acc * 85 + _b85dec[c]
          except TypeError:
              for j, c in enumerate(chunk):
                  if _b85dec[c] is None:
                      raise ValueError(
                          "bad base85 character at position %d"
                          % (i + j)
                      ) from None
              raise
          try:
              out.append(packI(acc))
          except struct.error:
              raise ValueError(
                  "base85 overflow in hunk starting at byte %d" % i
              ) from None
  
      result = b"".join(out)
      if padding:
          result = result[:-padding]
      return result
  
imports: import re
  import struct
  import binascii
label_desc: Use image node_id 20 for calling a global function with example usage: b85decode(b) and returns: result